Heat exchanger



J; PRICE HEAT EXCHANGER June 16,

Filed Dec. 12, 1929 2 Sheets-Shea! 2 1% ATTORNEYS Patented June 16, 1931 UNITED STATES PATENT ()F'FICE.

JOSEPH PRICE, OF STA]?Il'aIEl'JIOIbl', STATEN ISLAND, NEW YORK, ASSIGNOR TO THE GBISCOM-RUSSELL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE HEAT EXCHANGER Application filed December 12, 1929. Seria1 No. 413,491.

The present invention relates to improvements in heat exchangers of the type in which a plurality of tubes are placed within a containing shell, and which are commonly 5 known as the shell-and-tube, or surface type,

heat exchangers.

Such heat exchangers are used chiefly in transferring heat between two liquids, such for example as in oil refining operations, and in transferring heat between a liquid and a vapor or gas, as for example in steam power plants and industrial establishments. When used for transferring heat between two liquids, one liquid, for example water, is passed through the shell of the exchanger and comes into contact with the exterior surfaces of the heating tubes, while the other liquid,

for example oil, is sent through .the interior of the tubes. In transferring heat between a liquid and .a gas or vapor, the gas or vapor such, for example, as steam, is usually passed into the shell, and the liquid forced through the tubes. Y

Provision must be made for relative expansion between the shell and the tubes inasmuch as it is frequently desirable to make the tubesof different metal from that of the shell. Thus the tubes might be made of copper and the shell of steel, and these metals having difl'erent coefficients of expansion, a greater lengthening or shortening of the tubes as comparedwith the shell will take place for a given temperature change. Moreover, even when the tubes and shell are made of the same metal, there is not infrequently a difference in temperature between the interior of the tube bundle and the surface of the shell which will set up expansion strains.

One very practical way of taking care of 40 expansion and contraction-which has come into general-use, is found in the movable or floating head construction. In this construction ofheat exchanger one of the tube sheets is usually secured fast to the shell, while the other tube sheet, known as the floating tube is made to traverse the tubes twice it is known as a double pass exchanger, and so on. lVhere the liquid is made to traverse the tubes more than once it is customary to providev a cap on the movable or floating tube sheet to form with the tube sheet one or more chambers to receive the liquid from one portion of the tubes and redirect it into another portion of the tubes. This cap is fixedly secured to and therefore moves with the floating tube sheet as-it slides longitudinally under the forces of expansion and contraction. 7

It is important that the tube bundle, as nearly as possible, fill the interior of the shell so as to prevent the tendency of the fluid in the shell to pass along the space between the outer layer of tubes and the shell, instead of passing into the interior of the tube bundle and into contact with the surfaces of the interior tubes as well as those near the out-er part of the tube bundle. This tendency is known as short circuiting. It is also highly desirable to construct such heat exchangers so that the tube bundle including the two tube sheets can be removed as a unit from the shell for the purpose ofoccasi onal repair and periodical cleaning which the use of oil and other liquids which tend to form deposits on the surfaces of the tubes makes necessary.

In order to permit the removal of the tube bundle from the shell, the floating tube sheet must be made somewhat smaller thanthe interiorof the shell so as to pass through it. The cap covering the floating tube sheet is ordinarily of larger diameter than the tube bundle and accordingingly unless the diameter of the tube bundle is substantially less than that of the shell the bundle can not be withdrawn from the shell without first removing the cap from the floating tube sheet. As stated above, it is undesirable to have the tube bundle of much less diameter than the shell. Hence the desirability of providing a removable cap for the floating tube -sheet.

The principal object of the present invention is to provide a heat exchanger having a tube sheet which is removable through the shell to which is secured a cap or other member which is larger than the shell, the cap or other member being so associated with the tube sheet as to be readily removed therefrom to facilitate the dismantling of the exchanger.

A further object of the invention is to provide an improved form of clamping device or mechanism for securing the ca or other member to the tube sheet through t e use of which such member can be readily removed from the tube sheet in an improved manner when it is desired to dismantle the exchanger.

A particular object of the invention is to provide a heat exchanger of the movable or oating head type of improved construction in which the tube bundle substantially fills the interior of the shell, and 'in which the floating head is of improved construction,

whereby among other advantages the cap forming the floating chamber may be'readily removed from the tube sheet, and the tube bundle then removed as a unit from the shell.

While it has been proposed to secure such caps or other members to the tube sheets by means other than bolting the member directly to the tube sheet, as for example by means of sectional clamping rings, it is difficult to construct these sectional or divided clamping v rings in such a way as to avoid a tendency edge of the outer of the divided rings to rotate about the inner riphery of the tube sheet when the nuts on tli: clamping bolts are tightened. This canting of the ring sections tends to produce an insecure joint. A few. forms of sectional clam ing ring constructions have beenprdposed in which the canting referred to has been successfully avoided, but" at the expense of increasing the cost of manufacture. Arfurther articular object of the present invention is t erefore toprovide a construction in which the canting of the sectional rings is eliminated and which at the same time canbe manufactured cheaply.

The invention will be better understood by referring 'to the accompanying drawings in which there is illustrated by way of example a heat exchanger of the floating head type 1ntended chiefly for transferring heat between water and oil in oil refining operations. In these drawings: 7 l Fig. 1 is a longitudinal section of a heat exchanger embodying the invention;

Fig. 2 is a perspective view illustrating the the heat exchanger comprises the elongated .cylindrical steel shell 10 having an inlet 11 for water at one side, and an outlet 12 at the opposite side. "Supported within the shell is a tube bundle 13 made up preferably of a relatively large number of small thin-walled tubes'. These tubes are expanded at the right hand end into a fixed tube sheet 14 and at the left hand end into a movable or floating tube sheet 15. In order to cause the liquid entering at the inlet'll to pass longitudinally of the shell and of the tube bundle 13, a baflle plate 16 extends from the fixed tube sheet 14 centrally of the shell and to a point near the opposite end thereof.

The other fluid, for example oil, enters at the right hand end of the exchanger through an inlet 17 which delivers it to a chamber 18 from which it flows into the tubes which are on the upper side of the dividing partition 19. The liquid passes through these tubes and is discharged into the floating chamber 20 at the left hand end of the exchanger formed by the cap 21 which is secured to the floating in tube sheet 15 in a manner presently to be described. v v 1 This chamber 20 redirects the liquid into the tubes in the lower portion of the tube bundle 13 by which the llquid is returned to the right hand end of the exchanger and discharged into chamber 22 on the lower side of partition 19. The liquid then passes out through outlet 23. I

The shell 10 is provided at the right hand endzvith a connecting flange 24 and at the left han end with a similar flange 25. The fixed tube sheet 14 is clamped rigidly against flange. 24 by the castings 26. which contains inlet 17 and outlet 23 and which is held in position by a plurality of long bolts. 27. The shell 10 is closed' at the left hand end by means of a larger cover 28 which is boltedv to flange 25. The fluid passing through the shell is.

free to circulate within cover 28 around the floating head.

In order to support the floating head which comprises the floating tube sheet 15, the cap 21 and its associated parts, centrally of the cover 28, an annular" disc 29 is mounted on tube bundle 13 near the left hand. end of the exchanger. Disc 29 has a large central 0 ning in it so as to allow the free passage 0 the fluld in the shell into the cover 28. The disc is of suitable diameter to slide freelywithin tubes of the tube, bundle increase or decrease in length as they expand or contract through the changes in temperature.

Such relative movement of the tubes with respect to the shell may take place because of the fact that the tubes are made of different material from the shell and conse quently have a different coeflicient of expansion. It may also take place when the tubes of the shell are made of the same material because of the fact that the temperature within the tube bundle may and frequently is either higher or lower than the temperature of the shell.

The floating tube sheet 15 is just a little smaller in diameter than the interior of the shell 10 so that it will slide freely through it in removing the tube bundle. Cap 21 is provided with a thickened rim 30 having a plurality of holes 31 passing through it longitudinally and arranged preferably in equally spaced relation throughout its periphery. These holes are for the reception of stud bolts 32 which pass loosely through the holes and are threaded into a sectional ring. 33 posi tioned on the inside of the tube sheet 15. As

shown in Figs. 1 and 5, sectional rings 33 are semi-circular in form, but they may be' subdivided into smaller sections if desired.

The sectional ring 33 extends radially beyond the outer circumference 34 of the tube sheet, and is preferably of the same puter diameter as the rim 30 of cap 21. Placed on the outside of bolts 32 between sectional ring 33 and the rim 30 is a solid or continuous ring 35. Solid ring 35 is substantially the same thickness as the tube sheet 15 (see Fig.3), and the inner portion of the outer face of ring 35 is cutaway or relieved so as to leave a narrow ridge 36 as the only part of the ring in engagement with the inner face 37 'ofrim 30. This ridge is in engagement with the outer peripheryof the rim.

When nuts 38 on the outer ends of bolts 32 are tightened up, tube sheet 15 and solid ring 35 will be clamped between sectional ring 33 and the rim 30. of cap 21..- The portion 39 of the inner face of rim 30 which lies toward the center of the. heat exchanger from bolts 32 will be forced against the outer face of tube sheet 15, and the outer face of sectional ring 33 will be forced against the inner face of tube sheet 15, and a tight joint will be ef'fectedbetween the cap 21 and the tube sheet so that leakage will be prevented from chamber 20. I

A To facilitate the making of a tight joint at this point, the outer face of tube sheet 15 is recessed as shown at 40 and the flat surfaceof this recess is finished smooth. Also the portion 39 of the inner face of rim 30 is made relatively narrow and finished smooth. By making this portion 39 narrow, it is compara tively easy to finish it properly and. the pressure between it and thetube sheet is increased for a given stress in bolts 32.

The sectional ring 33 is of plain rectangular cross section as shown in Figures 1 and 3 and is therefore easily and cheaply manufactured. It is not necessary that more than ordinary accuracy be used. Liberal tolerances may be allowed since it is not necessary to make the ring 33 fit the tube sheet 15 accurately. Ring 33 serves merely as a bridge between the inner surface of tube sheet 15 and solid ring 35. The employment of solid ring 35 thus prevents the canting of sectional ring 33 without the necessity of accurate machine work for this purpose.

Solid ring 35 can also be manufactured cheaply as the tolerances again may be liberal. It is preferable to have the thickness of solid ring 35 equal to the thickness of the tube sheet, but variations in thickness which occur in the course of ordinary manufacturing operations may be allowed,

As may be seen from Figs. 1 and 2, the assembling and disassembling of my improved heat exchanger is made very easy. In assembling the exchanger the tube bundle is in serted within shell 10, and annular disc 29 serves to accurately support and center the tube bundle as it slides'through the shell, maintaining it in the proper position when the tube sheet reaches its final location at the left hand end. After the fixed tube sheet14 has been properly secured in place, the assembling of the floating head proceeds.

The stud bolts 32 are first set up tight in ea h of the'halves of sectional ring 33. Thenon the inside of the tube sheet as shown in Fig. 2. Bolts 32 rest upon the periphery of the tube sheet and this half of the sectional ring isthus held in place merely by gravity. The lower half of the sectional ring isplaced in position and held there by a jack or other suitable support. The bolts 32 again serve to position this half of the sectional ring also.

The solid or continuous ring 35 is then slipped over the bolts 32. In Fig. 2 this ring is shown in position just ready to be slipped over these bolts. When ring 35 has been placed over the bolts it serves to hold both sections of the sectional ring 33 and" the jack if used may be removed from the lower section. The cap 21 may then be moved up from the'position shown in Fig. 2 so'as to receive the bolts 32 and mute 38 may be applied and screwed home which completes the assembly of the floating head. After this it is only necessary to bolt the cover 28 in position on flange 25.

In disassembling the floating head end of the heat exchanger, after the removal of the of the cover 28 and the cap 21, the solid ring 35 again serves to hold the halves of sectional sufiiciently smaller than said shell to be easily removable therethrough, a cap for said tube sheet larger than the interior ofthe shell and havin a rim engaging the outer face of the tube s eet, asectional ring disposed inwardly of said tube sheet and engaging the inner face thereof, a continuous ring disposed in the plane of the tube sheet and serving to space the sectional ring from the rim of the cap, and a plurality of bolts for clamping said parts together. I I

2. A heat exchangerof the class described comprising a shell, a tube bundle therein, a

tube sheet for one end of the tube bundle sufficiently smaller than said shell to be easily removable therethrough, a cap for said tube sheet larger than the interior of the shell and havin a rim engaging the outer face of the tube s eet, a sectional ring disposed inwardly of said tube sheet and engaging the inner face thereof, a plurality of bolts joining said sectional ring and the rim of the cap, said bolts extending past the outer periphery of the tube sheet, and a continuous rin positioned outside of said bolts between the sectional ring and the rim of the cap and having a nar-i row ridge at its periphery in contact with said rim.

3; A heat exchanger of the class described a tu e sheet for one end of the-tube bundle sufiiciently smaller than said shell to be easily removable therethrough, a cap for said tube sheet larger than the interior of the shell and having a rim engaging the outer face of the tube sheet, a flat sided sectional ring having one of its fiatsides lying against the inner face of said tube sheet, a plurality of bolts joining said sectional ring and therim of the ca and a continuous ring disposed outside 0 said bolts between the sectional ring and the rim of the cap, said ring being substantially rectangular in" cross section but having a narrow ridge near its periphery in -contact with the rim.

4. A heat exchanger of the class described comprising a shell, a tube bundle therein, a

comprising a shell, a tube bundle therein,

removable therethrough, a cap for said tube sheet having a rim substantially larger in diameter than the tube sheet, said rim having an annular face, a plurality of bolt holes spaced around said rim and passin through said annular face, a portion of said annular face bein in contact with the outer marginal edge of t e tube sheet, a fiat sided sectlonal ring of substantially the same width as the annular face of the rim of the cap lying against the inner marginal edge of the tube sheet, a continuous rlng disposed between said sectional ring and said rim outside of said bolt holes and havin a narrow ridge near its edge in contact w1th said rim, and bolts joining said sectional ring and said rim and fitting loosely within said bolt holes.

5. A heat exchanger of the class described comprising a shell, a tube bundle therein, a

tube sheet. for one end of the tube bundle sufficiently smaller than said shellto be easily removable therethrough, a cap for said tube sheet havin a rim engaging the outer faceof the tube s eet, a sectional ring disposed inwardly of said tube sheet and engaging the of the tube sheet, means engaging the inner face of said tube sheet, a continuous ring disposed in the plane of the tube sheet and serving to space the said means from the rim of the cap, and a plurality of bolts for clamping said parts together. I

7. A heat exchanger of the class described comprising a shell, a tube'bundle therein, a tube sheet for one end of the tube bundle suificiently smaller than said shell to'be easily removable therethrough, a cap for said tube sheet larger than the interior of the shell and having a rim engaging the outer face of the tube sheet, a sectional ring disposed inwardly of said tube sheet and engaging the inner face thereof, removable means disposed in the plane of the tube sheet and serving to space the sectional ring from the rim of the cap, and a plurality of bolts for clamping said parts together.

8. A heat exchanger of the class described comprising a shell, a tube bundle therein, a tube sheet for one end of the tube bundle sufficiently smaller than said shell to be easily.

thereof, clamping means enga ing the inner face of said tube sheet, remova 1e mea'ns disosed in the plane of the tube sheet and servmg to space the clamping means from the rim of the cap, and means for securing said, parts together.

9. A heat exchanger of the class described comprising a shell, a tube bundle therein, a tube sheet for one end of the tube bundle sufficiently smaller than said shell to be easily removable therethrough, a cap for said tube 1 sheet larger than the interior of the shell and having a rim engaging the outer face of the tube sheet, a sectional ring in clamping engagement with said tube sheet, removable means disposed substantiallyin the plane of said tube sheet and enga "ng said sectional ring, and a plurality of olts for clamping said parts together.

10. A heat exchanger of the class described comprising a shell, a tube bundle therein, a tube sheet for one end of the tube bundle sufficiently smaller than said shell to be easily.

removable therethrough, a cap forsaid tube sheet larger than the interior of the shell and having a rim engaging the outer face of the tubeshe'et, a sectional rin in clamping en-' gagement with said tube s eet, a continuous ring disposed substantially in the plane of the tube sheet and engaging said sectional ring, and a plurality of bolts for clamping said parts together.

11. A heat exchanger ofthe classidescribed comprising ashell, a tube'bundle therein, a tube sheet forone end of the tube bundle sufficiently smaller than said-shell to be easily removable therethrough, a cap for said tube sheet having a rim engaging the outer face of the tube sheet, a sectional ring in clamping engagement with said tube sheet, removable means engaging said sectional ring, and a plurality of bolts for clamping saidparts together.

12. A-heat exchanger of the class described comprising a shell, a tube bundle therein, a tube sheet'for one end of the tube bundle sufficiently smaller than said shell tobeeas ily removable therethrough, a floating head for said tube sheet of larger diameter than the interior of said shell and comprising a-capclamping means is apnheet havingarimthe outerhce canting oi said the inner face of the of the tube sheet, a sectional ring in spaced relation to said cap and in clampmg-engagement with said tube sheet, removable means engaging said sectional ring, and a plurality of bolts for clamping said parts together, said removable means being arranged to prevent canting of said sectional ring when said parts are clamped together.

In testimonywhereof I afix my slgnature.

JOSEPH PRICE. 

